A supply chain supplies products to one or more customers in response to demand. A supply chain may include nodes that store inventory such as the products or components or materials needed to produce the products. The flow of items through the nodes of a supply chain may be subject to feasibility constraints. Some known techniques for determining the amount of inventory to maintain at each node take into account these feasibility constraints. According to one known technique, the amount of demand that may be satisfied with an unconstrained network is calculated, and the demand is then decreased on an ad hoc basis to account for the feasibility constraints. According to another known technique, the flow of items through the supply chain is simulated using assumptions about the feasibility constraints. These known techniques for determining inventory in accordance with feasibility constraints, however, may be inefficient and may fail to provide a desired level of accuracy.